Abstract: A wireless telephone engine, smart-card engine and Personal Digital Assistant (PDA) engine are integrated in a single device, wherein an address book is shared by the wireless telephone engine and PDA engine. An associated display unit including a touch screen is coupled to the PDA. The smart-card engine is configured to communicate with external devices via a short-range transceiver. Additionally, the PDA engine is configured to automatically balance an electronic account ledger based upon point of sale transactions, and control a remote device by transmitting signals to the device via the short-wave transceiver and/or the wireless telephone engine. The PDA engine is also configured to receive signals from the remote device regarding the status of the remote device. Further, the PDA engine is configured to exchange data with a remote computer via the wireless telephone engine. The exchanged data includes information stored within the PDA engine and the address book.